docstr: Update online state based on the provided test instance.
  
  Parameters
  ----------
  x_t
      The test instance.
docstr_tok: ["Update","online","state","based","on","the","provided","test","instance",".","Parameters","--","--","--","--","--","x_t","The","test","instance","."]
code: def _update_state(self, x_t: torch.Tensor):  # type: ignore[override]
      """
      Update online state based on the provided test instance.
  
      Parameters
      ----------
      x_t
          The test instance.
      """
      self.t += 1
      kernel_col = self.kernel(self.x_ref[self.ref_inds], x_t)
      self.test_window = torch.cat(
          [self.test_window[(1 - self.window_size) :], x_t], 0
      )
      self.k_xy = torch.cat(
          [self.k_xy[:, (1 - self.window_size) :], kernel_col], 1
      )
  
file_path: alibi-detect/alibi_detect/cd/pytorch/mmd_online.py
imports: from tqdm import tqdm
  import numpy
  import torch
  from typing import Any, Callable, Optional, Union
  from alibi_detect.cd.base_online import BaseMultiDriftOnline
  from alibi_detect.utils.pytorch import get_device
  from alibi_detect.utils.pytorch.kernels import GaussianRBF
  from alibi_detect.utils.pytorch import zero_diag, quantile
  from alibi_detect.utils.frameworks import Framework
  from alibi_detect.utils._types import TorchDeviceType
label_desc: Use image node_id 5 for calling the MMDDriftOnlineTorch obj's underlying member method code with example usage: obj._update_state(x_t) without return types